The series began as a fairly humorous and lighthearted satire of Japan's teenage delinquent-gang subculture told from the perspective of Matsushita Tadashi (who also narrates these early Karate Bu stories), a 2nd year student at Kangokou High and a constant target of Kangokou's numerous bullies who beat him up routinely after school. He is almost always accompanied by his best friend Saitou Takaki, who is also constantly harassed. As the pair grow increasingly tired of being victimized they decide to join the titular Karate Club, which is notorious throughout Osaka's youth gangs for training and producing the city's most hardened and toughest teenage thugs while maintaining the facade of a legit school sports club. But when they join the club, they find themselves picked on just as much if not worse by the club's current members. But as the story progresses they grow to be increasingly capable fighters.

As the series went on it gradually changed its tone to a more serious and violent martial arts manga, with the narrative shifting from the perspective of Matsushita to Takagi Yoshiyuki, the smart mouthed, tough-as-nails captain of the Kangokou Karate Club.

Along with the manga's change in attitude and central character, the various teenage fighters throughout the series grew increasingly stronger and even began to tap into superhuman ki abilities, putting Osu!! Karate Bu in the company of other similar epic Shōnen fighting manga such as Yu Yu Hakusho, Dragon Ball, and Fist of the North Star.

Osu!! Karate Bu was wildly popular in its native Japan, but is otherwise almost completely unknown in most other countries. It spawned a four episode OVA mini-series released over a period of two years from 1990-1992, a 1990 live action movie, and a 1994 Super Famicom fighting game.

I'm only 57 chapters into this manga, but I don't see how can this be compared to Dragon Ball and the like.The art is rather bad to start with, the characters making these ridiculous expressions in order to show comedy. It might have been funny and interesting in the 80's but to me it hasn't aged well.Then you have some super serious chapters that mention rape and death, and the themes aren't well handled to be honest. There are still plenty of chapters to go, with this one having a staggering 43 volumes, and unless the changes mentioned are really awesome I don't see how its rating will improve.For now it gets a 5, meaning that I'm curious but not very hopeful, after another 100 chapters or so I might update the rating and comment.